Variable pitch propeller



Oct. 2, 1962 A. MaCFARLAND 3,056,457

VARIABLE PITCH PROPELLER 2 Sheets-Sheet 1 Filed March 3, 1961 1 55 5 E Rab/n /40a/'r Mac/ar/md L L 4 L 5 INVENTOR.

Oct. 2, 1962 A. M FARLAND 3,955,457

VARIABLE PITCH PROPELLER 2 Sheets-Sheet 2 Filed March 3, 1961 INVENTOR.

A7 Af0RN7Y United States Patent 3,056,457 VARIABLE PITCH PROPELLER Robin Adair MacFarland, Lakeland, Fla. Filed Mar. 3, 1961, Ser. No. 93,216 7 (Ilairns. (Cl. 170160.45)

This invention relates to variable pitch propellers. While certain aspects of the present inventive concept are broadly applicable to a wide variety of blade type propellers and impellers for liquid or gaseous blade reaction, that form of the invention here shown by way of illustration is particularly adapted for a pitch control of the blades of an outboard or inboard motor propeller. While the present construction is admirably adapted for effective and efiicient use in this particular field, it will of course be understood that the principles of the invent-ion as herein set forth are in no Way limited to such an application.

In the field of outboard motor propellers in particular, considerable difiiculty has been experienced in efforts to provide for adjustments of the blade tilt. In particular, there has not heretofore been provided adequate means for the variation of pitch during rotation of the propeller. Such variation during operation however is much sought after, particularly in the operation of small craft when used as tow for water skiing. In this particular instance a fast start under maximum load is desirable, calling for a minimum pitch commensurate with power capacity. After a desired speed is approximated, however, a greater pitch will be adequate and will be more eliicient with respect to power consumption. These and other considerations have raised the problem of providing simple, effective and efiicient remote pitch control operable during the rotation of the propeller.

In the present invention such a means is provided. The structural arrangement herein being particularly adapted to the application of outboard motor propellers. In general terms, that form of the invention herein set forth may be broadly defined as providing fluid pressure means remotely controlled for affecting the change in blade angularity while the propeller is in rotation. More specifically, the invention as here shown may be char acterized as including propeller blades having geared hubs seated in the propeller hub together with fluid actuating racked pistons. The racks of the pistons engage the blade gears in the propeller hub, whereby reciprocation thereof induces a rotational blade to vary the pitch. Among the features of the invention is the provision of a single actuating means for the racks of at least one series of racks for all blades to insure uniform adjustment of all the blades simultaneously. Another important feature of t.e invention is the provision of a pair of opposed racks for each blade gear. Thus, as fluid pressure, preferably hydraulic, is applied in one direction to move one set of the racks under power in one direction, the opposed racks will be automatically moved in the opposite direction. This arrangement is such that the relative position of the actuating means for the racks at one side of the blade gears, automatically adjust the operating mechanism for racks on the other side of the gears to position their operating means for pressure responsive action when the blades are to be reversed from the direction of adjustment induced by pressure for the original movement.

From the foregoing, it will be seen that the objects of the present invention include that of providing a novel and improved means for adjusting angularity of propellers or impeller fluid reaction blades. More specifically, an object of the present invention includes that of providing means for adjusting the angularity of propeller or impeller blades during the rotation of the propeller or impeller. In that present form of the invention it is further an object of the invention to provide a field actuated remote 3,13 55,45? Patented Get. 2, 1962 "ice control means for altering the pitch of outboard motor propellers while the propellers are in operation. A further object of the invention is to provide a propeller pitch control by which either forward or reverse motion of the craft may be achieved from but a simple direction of drive for the propeller shaft. Numerous other objects, features and advantages of the present invention will be apparent from consideration of the following specification taken in conjunction with the accompanying drawings, in which FIG. 1 is a side elevation of one form of the present preferred form of the invention,

FIG. 2 is a longitudinal section through that form of the invention shown in FIGURE 1, taken at right angles to the plane of the illustration of FIGURE 1. In both instances, for clarity sake, only one single blade is illustrated,

FIG. 3 is a section taken on the lines 3-3 of FIG- URE 2,

FIG. 4 is a similar section taken on the lines 44 of FIGURE 2, and

FIG. 5 is a section taken on the lines. 5-5 of FIG- URE 2.

Referring in detail to the drawings, the propeller drive shaft is indicated by the numeral 10, and may be of any of various conventional forms. The shaft here shown by way of illustration, is that of a conventional type outboard motor. Other diameters and general constructions of inboard and outboard shafts may be readily accommodated for use in the present construction by adapted drive sleeves hereinafter discussed. Since the present mechanism is capable of a complete reversal of the propeller pitch, reverse drive may be secured without the necessities for a reverse mechanism of the directional drive of the drive shaft itself.

The adapters sleeve is indicated by the numeral 11, and may be of such internal design with single or double diameters as to accommodate the general construction of such propeller drive shaft as may be employed. The particular shaft here shown by way of illustration, is illustrated as including a reduced portion of 12 and further reduced terminal 13. The internal configuration of the adapters sleeve 11 is formed to fit and accommodate such terminable portions of the shaft 19. It will, of course, be understood that in various types of propeller shafts the internal construction of the adapters sleeve will be modified in such manner as to properly accommodate various types of shaft ends.

Propeller shaft 10 is secured to the adapters sleeve by staked drive pins 14 and 15. Pin 14 extends through the reduced portion of 12 to engage the adapters sleeve and through to engage the propeller blade shaft hub 31 for turning the hub with the shaft as hereinafter described. The pin 15 is secured to the further reduced portion 13 to engage the sleeve. Outwardly beyond the shaft end, the adapters sleeve is provided with the reduced portion 16 accommodating a conventional shear pin 17 extending through the adapter to engage an inner hub sleeve 20, while a further extended terminal end 21 is provided with a cotter pin 22 to engage a propeller tail cap 23. A drive hub cover cap 24 is engaged between the tail cap 23 and an outer hub sleeve 25 which is connected and sealed by an intermediate rubber sleeve 26 of the main drive hub.

The main drive hub 18 includes the propeller blade shaft hub 30 fixed for rotation with the main drive hub and defining blade hub recesses indicated at 31 within which the blade hubs 32 of the blades 33 are seated. An inner flange 34 of the blade hubs is formed to secure the hub within the recess of 31 by shaft hub-retaining rings 35.

Within the recess 31 each hub is provided with a splined hub or gear 36. Recesses 31 are of such dimension as to afford room on each side of each hub or gear 36 for toothed racks 37 and 38. By this arrangement it will be seen that since the racks engage the splined hubs or gears on opposite sides of the axis of the blades rotation of the hubs and consequently of the blades will result from equal and opposite movement of the racks whereby to vary the blade pitch.

For movement of the outer rack shaft 37, there is provided an outer ring 40 mounted within the main drive hub 18 formed as an extension of and rotating with the body of the blade shaft hub 30. Against the front face of the ring 40 the rear bases 42 of the rack bars 37 rest, whereby forward movement of the plate induces forward movement of the racks 37. Since the ring 40 rotates with the hubs and the racks no friction is encountered therebetween. For a further understanding of the operation, it is to be noted that as the racks 37 move forwardly under the influence of forward movement (to reverse the blades) the opposite racks 38 must of necessity move in the opposite rearward direction. This is made possible by the bearing of the bases 43 of the racks 38 against an inner ring 44.

With respect to the disclosure of FIGURE 2, it will be seen that the inner and outer rings 44 and 40 are in parallelism, which indicates a neutral position for the angularity of the blades and that when rotary movement of the propeller blade hubs, and thus a change in the propeller blade pitch takes place, the inner and outer rings move with respect to each other, the one equal and opposite to the other. Behind each ring there is provided an inner friction ring 46 and behind and in contact therewith there is provided inner and outer non-rotary rings 47 and 48 respectively. For movement of the outer ring 40 there is provided an outer circular series of plungers here shown as three, mounted in the rear stationary housing 41 and which bear at the outer end against a spring pressed outer non-rotating plate 49. The chamber 54 behind plate 49 may be served by an outer fluid passage 55. Similarly, for operating the inner ring 44, there is provided a series of plungers 56 bearing against an inner spring urged plate 58 which is served by an inner passage 60.

In the operation of the device, when pressure is applied to the channel 55, to the outer series of plungers, their companion plunger 50 is pressed forwardly, moving the outer ring 49 and hence the rack 37 to turn the propeller blade hub in a reverse direction. Since in this action the opposite inner rack must, perforce, be urged rearwardly, this will move the inner ring against which they bear rearwardly and the inner plungers will move their plate rearwardly compressing its springs. If now the pressure is reversed, being admitted to the inner cylinders through the channels 60, the inner ring will move forwardly through action of its plungers and the rack bar 38 will move reversing the direction of the pitch and causing a rearward recession of the racks 37. Thus by selecting the application of pressure between the outer channel 55 and the inner channel 60 the pitch of the blades may be reversed by remote control and without terminating rotation of the propeller.

It will, of course, be understood that in the operation of the invention, numerous changes, modifications and the full use of equivalents may be resorted to without departing from the spirit or scope of the invention as outlined in the appended claims.

What I claim is:

1. Apropeller including a hollow hub, impeller blades mounted on said hub and extending radially therefrom, splines on said blades within said hub constituting gear teeth, a pair of opposed rack bars engaging the gear teeth of each blade, remotely controllable fluid pressure operating means common to one rack bar of each blade, and a separate remotely controllable fluid pressure operating means common to the opposed rack bar of each blade.

2. A propeller including a hollow hub, impeller blades mounted on said hub and extending radially therefrom, splines on said blades within said hub constituting gear teeth, a pair of opposed rack bars engaging the gear teeth of each blade, remotely controllable fluid pressure operating means common to one rack bar of each blade, and a separate remotely controllable fluid pressure operating means common to the opposed rack bar of each blade, said fluid pressure means being operable during rotation of said blades.

3. A variable pitch propeller, including a hub, a plurality of impeller blades extending radially from said hub, gear teeth on said blades within said hub, an outer circular series of rack bars within said hub each one of which engages the gear teeth of one of said blades, fluid pressure means for simultaneously moving said outer circular series of rack bars, an inner circular series of rack bars within said hub each one of which engages the gear teeth of one of said blades on the opposite side of engagement of said teeth by said outer circular series of rack bars and independent positively acting fluid pressure means for actuating said inner series of rack bars.

4. A variable pitch propeller, including a hub, a plurality of impeller blades extending radially from said hub, gear teeth on said blades within said hub, an outer circular series of rack bars within said hub each one of which engages the gear teeth of one of said blades, fluid pressure means for simultaneously moving said outer circular series of rack bars, an inner circular series of rack bars within said hub each one of which engages the gear teeth of one of said blades on the opposite side of engagement of said teeth by said outer circular series of rack bars and independent positively acting fluid pressure means for actuating said inner series of rack bars, said means including one circular series of pistons for each series of rack bars and a common source of fluid pressure for each circular series of pistons.

5. A variable pitch propeller, including a hub, a plurality of impeller blade extending radially from said hub, gear teeth on said blades within said hub, an outer circular series of rack bars within said hub each one of which engages the gear teeth of one of said blades, a single outer operating ring engaging said outer series of rack bars, fluid pressure means for actuating said outer operating ring, an inner circular series of rack bars within said hub, each one of which engages the gear teeth of one of said blades on the opposite side of engagement of said teeth by said outer circular series of rack bars, a single inner operating ring engaging said inner series of rack bars and a separate fluid pressure means for actuating said inner operating ring.

6. A variable pitch propeller, including a hub, a plurality of impeller 'blades extending radially from said hub, gear teeth on said blades within said hub, an outer circular series of rack bars within said hub each one of which engages the gear teeth of one of said blades, a single outer operating ring engaging said outer series of rack bars, fluid pressure means for actuating said outer operating ring, an inner circular series of rack bars within said hub, each one of which engages the gear teeth of one of said blades on the opposite side of engagement of said teeth by said outer circular series of rack bars, a single inner operating ring engaging said inner series of rack bars and a separate fluid pressure means for actuating said inner operating ring, both of said fluid pressure means including a cylinder and piston corresponding with each rack bar actuated by each ring.

7. A variable pitch propeller, including a hub, a plurality of impeller blades extending radially from said hub, gear teeth on said blades within said hub, an outer circular series of rack bars within said hub, each one of which engages the gear teeth of one of said blades, a single outer operating ring engaging said outer series of rack bars, fluid pressure means for actuating said outer operating ring, an inner circular series of rack bars within said hub, each one of which engages the gear teeth of one of said blades on the opposite side of engagement of said teeth by said outer circular series of rack bars, a single inner operating ring engaging said inner series of rack bars and a separate fluid pressure means for actuating said inner operating ring, both of said fluid pressure means including a cylinder and piston corresponding with each rack bar actuated by each ring, and a common source of fluid pressure for the pistons corresponding to the outer series of rack bars and a separate common source of fluid pressure for the pistons corresponding to the rack bars of the inner series.

References Cited in the file of this patent UNITED STATES PATENTS Connors Sept. 30, Unterberg July 18, Eves Aug. 1, Hardy Jan. 6, Peterson Mar, 1, Steiner July 22,

FOREIGN PATENTS Germany Feb. 13, 

